Touch screen displays are human interface devices that allow individuals to provide input to a computer system by physically touching specific regions of the display with their fingers. The regions selected will correlate to the input they wish to provide and will be visually identified on the display by specific text or graphics. Because human hands and fingers secrete oils and carry other contaminants, such materials are deposited on touch screen displays during the normal course of their operation. Deposits of such contaminants on the display increase reflectances which can eventually render the display unusable when the user can no longer read information being displayed or determine which regions of the screen should be selected to provide a desired input.
For some applications, such as portable personal electronic devices, this degradation may not be critical because the purpose of the device is a matter of personal convenience and not critical to the operation of machinery or safety. In addition, touch screen displays on portable personal electronic devices are easily cleaned, such as by wiping the screen clean using an available article of clothing. In other applications such as aircraft avionics systems or industrial plant control rooms, opportunities to clean displays are much more limited. For example, a flight crew should be able to concentrate on priorities higher than periodically cleaning their instrumentation when their aircraft is in flight. Further, cleaning touch screen displays that control in service equipment is not desired because of the risk of inadvertently activating or de-activating system functions or altering configurations. Low surface energy films which are oleophobic have been introduced that partially address the issue of contaminant induced reflectances on touch screen displays. However, while such films often mitigate against increases in specular reflectances, they tend to increase the development of diffuse reflectances, which also negatively affect optical performance of the display.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the specification, there is a need in the art for improved systems and methods for smudge control for touch screen human interface devices.